It's summertime, and the company behind the Uber car-hailing service wants you to stay cool.

Using their app, of course.

As part of a one-day promotion on Friday, Uber users in dozens of cities could hail an ice cream truck instead of the usual black car, SUV or taxi. A truck with an Uber logo on the side would then show up, hang around long enough to distribute some ice cream, and head off to make another delivery.

The ice cream wasn't cheap -- but then again, free delivery was included. In San Francisco, users had to spend $30 to have a truck come to their location, and for that they got five ice creams and a token gift.

The promotion was held in 33 cities where Uber operates including Rome, Berlin, Toronto, New York and Paris.

Uber was pushing the sweet stuff to get noticed in a year when it has big goals. It's currently operating in 37 cities and wants to be active in 100 by the end of 2013.

Uber has teamed up for one-day promo events before. Last Cinco de Mayo users could order a mariachi band to serenade them. They've also dispatched flowers and musicians on Valentine's Day. The ice cream stunt was done last year too, though on a smaller scale.

"Every once in a while, it's fun to take the technology we have and use it for something fun," said Uber spokesman Ilya Abyzov.

Uber wasn't the only company offering promotions this week. Just as it was urging its users to scream for ice cream, Sidecar launched a promotion in which users who take three rides this weekend can enter a drawing for a US$1,000 bike.